Reply to “Dyslexia: Still Not a Neurodevelopmental Disorder”

Abstract

In a recent opinion article, we explained why we think that defining developmental dyslexia as a neurodevelopmental disorder and neuroimaging studies on dyslexia are useful. A recent response has made some claims of generalized misinterpretation and misconception in the field. Since that was a direct reply to our article, we would like to clarify our opinion on some of those claims.

Document Analysis of State Dyslexia Legislation Suggests Likely Heterogeneous Effects on Student and School Outcomes

“…In other words, the synergy between the IDA definition of dyslexia and the Simple View of Reading may help explain the popularity of the former. This potentiality seems likely considering that are ongoing scientific disagreements about how dyslexia should be defined (Brady, 2019; Fraga González et al, 2019; Miciak & Fletcher, 2020; Protopapas & Parrila, 2019), with different definitions often reflecting the objectives of researchers working in different disciplines (e.g., education, cognitive psychology, neuroscience; Tønnessen, 1997).…”

Putting the Identification of Dyslexia into a Multi-Level Perspective

“…In this journal, Protopapas and Parrila [ 5 ] questioned the use of the “neurodevelopmental disorder” umbrella to frame dyslexia. This proposal has spurred a hot debate among other researchers who are convinced of the usefulness of considering dyslexia as a neurodevelopmental disorder [ 6 , 7 ].…”

“…Certainly, we cannot rule out that a very specific biological defect will be discovered in the future; but should we call “neurodevelopmental disorder” a difficulty in which the biological and neural signature has yet to be identified? Of course, this is open to discussion and on various occasions, Fraga González, Karipidis and Tijms [ 6 , 7 ] have expressed their opposing view in this journal. To sum up, what seems clear is that the “neurodevelopmental disorder” label should not be assigned without explicitly stating why the definition is being given and its implications for clinical practice.…”

“…Much of the controversy over the nature, and indeed, the existence of dyslexia might be better understood when seen in a multi-level analysis approach, a perspective originally claimed by Frith [ 17 ]. Still, the recent debate, which appeared in Brain Sciences [ 5 , 6 , 7 , 18 ], raises questions as to whether one should accept the direct implication that all levels are causally involved in dyslexia. Along these lines, Frith [ 17 ] states that “ Dyslexia can be defined as a neuro-developmental disorder with a biological origin and behavioural signs which extend far beyond problems with written language .” By contrast, based on Protopapas and Parrila’s [ 5 , 13 , 18 ] comments, one can propose that the behavioral level is sufficient in order to efficiently and reliably define dyslexia and adding complexities inherent to other levels of analysis (such as the “neuro-developmental disorder” label or cognitive markers beyond reading) could lead to unwanted complexities in the diagnostic procedure.…”